Q: about difference of telephoto and telezoom lens

[mikko2007]

can you please describe and tell me the difference of both the lenses. the purpose of each lens.. thanks...

[green]

A telephoto is a fixed focal lense. A telezoom is a variable focal lense.

[Keitht]

To expand the previous answer - a 70-200 telezoom can be adjusted to provide the field of view, and image size, of any lens between those 2 figures.

[Emiel_Skyfreak]

But optically most zoom lenses are less good than a prime lens..although there really are zoom lenses that kick some primes their asses regarding contrast, bokeh, sharpness etc.

Don't forget a modern kitlens is also a zoomlens, but not a telezoom lens ;) (wide angle to standard/moderate tele) Most of the times they are 18-55's for dSLR's and 28-75/80/90 for film SLR's.
Most telezooms (for dSLR's) feature a range of 70-200mm or 70/75-300mm, but there are many others available, like a 50-150mm, 100-300mm, 50-500mm, 200-500mm etc.

[Keitht]

Generally speaking a zoom lens with a minimum focal length of under 50mm e.g. 28-80 would be referred to a wideangle zoom. Those with minimum focal length over 50 mm would be referred to as tele(photo) zoom.